The best way to deflect incoming asteroids? Forget nuclear blasts, "gravity tractors" or  Bruce Willis or Clint Eastwood in a souped-up space shuttle: according to a new study at the University of Glasgow, focusing sunlight onto an asteroid with space-based mirrors is the way to go.

Mind you, it would take 5000 space mirrors to fend off something of the size the killed off the dinosaurs–more than five kilometres across–but you wouldn’t need nearly as many for smaller ones. (Via New Scientist Space.)

Other options considered in the study: ramming a spacecraft into the asteroid at high speed, digging up pieces of it and shooting them off into space, attaching a thruster, or painting one side to cause trajectory-deflecting uneven heat radiation. (Illustration: M Vasile et al, University of Glasgow.)

[tags]spacecraft, asteroids, planetary defense[/tags]